The winner of the World Cinema Documentary Editing Award at this year’s Sundance Film Festival, writer/director Yael Hersonski’s documentary “A Film Unfinished” forces viewers to reconsider the use of historical footage in holocaust films.

A cinematic endeavor over four years in the making, Hersonski’s doc shines a new light on a now infamous Nazi-made propaganda film shot in Warsaw’s Jewish ghetto in 1942. Previously considered — and presented — as accurate footage of the era, a new reel of the footage (titled “Das Ghetto”) was discovered in 1998 that proved beyond a doubt that Nazi filmmakers were actually manipulating and forcing Jewish ghetto residents into staging ghastly and misleading scenes of “real life” — rich Jewish ghetto dwellers pretending to ignore poorer neighbors, for example — for propaganda purposes. Hersonski’s film now shows all of this raw footage in its entirety for the first time.

Hersonski says she first began investigating the old Warsaw ghetto footage while doing research for a screenplay she was writing. “[My project] probably looked more like an essay at the beginning,” she said. “But it was my way of examining, in a theoretical way, the testimonial value of the cinematic image.”

The director, who is based out of Tel Aviv, adds that she was interested in going back to a time before viewers were constantly being bombarded with images of violence and atrocities on the news and online. “I was fascinated by the idea of examining how our ability to view our world today through TV and film screens has grown in a more critical way, with more ethical awareness.”

Hersonski spoke to us about the development of her film, and how she feels about the MPAA’s decision to give “A Film Unfinished” an R-rating for its use of “disturbing images of Holocaust atrocities, including graphic nudity.”

The Wall Street Journal: You first came to find this footage about four and a half years ago, after it was brought to your attention by director/producer Noemi Schory.

She directed me to watch various scenes of footage from that time period [during World War II]. At the time, she just finished a vast project producing 100 archive-based shorts for the new visual center of our main Holocaust memorial museum [Yad Vashem]. So she knew more or less almost everything that existed in the film archives. When I saw this [footage], I was amazed not only by the intensity of the images, but also, their very existence, which even at my age, I was not aware of. It’s surprising because the footage is accessible — film archivists know it very well; it was just not fully exposed to the public. Of course, I already knew some of the images in this film for they’ve been used many many times in documentaries — without the context of the full sequence.

Well, I don’t think it’s going to damage the theatrical life of this film. We now have more people that are talking about it, so that‘s good. But I am sorry that fewer students are going to be able to see it because I truly believe it has value and doesn’t merely show the [graphic] images, but discusses their nature. So it’s not just about showing nude women, but discussing the the context.

How much more undiscovered footage is out there? And how much of today’s known footage might still be misinterpreted?

I’m sure there is more footage to discover — maybe not a massive quantity, but there is always a drawer that’s not yet been opened. Regarding other footage that has been used — or misused — in a specific way, I don’t really know. I can only give you an example: Most of the documentaries abut the holocaust, at a certain point, use images of trains, usually in the context of Jews that were moved to extermination camps in trains. So we see footage of trains and it makes sense to believe that inside the trains, there are Jews. But the truth is that there are only two filmed documentations of such trains. All the other trains are filled with commodities.

Does it make a difference?

I guess so. And also, I’m aware of the fact that during the first decades [after the holocaust], it was important to just deliver a message that these things did happen and make that information as communicative as possible. It was not enough to tell the story; they also wanted to use footage in order to illustrate the story. But today, we can already discuss the nature of those events, and not everything we see is what we see. Nothing is objective; it’s always done through a certain prism and a certain point of view.

What’s the future for the film?

The distribution company here will release the DVD and of course it will have additional features, such as more historical information regarding the time and the archives. For myself, the archival footage is something that I’m still intrigued to explore. It’s an infinite subject matter and I feel like I’m only at the beginning of this journey.

“An Unfinished Film” will open in New York Aug. 18 and Los Angeles Aug. 20, followed by a national rollout.